Sonnen, who will fight light-heavyweight champion Jon “Bones” Jones in April, is widely recognized as one of the top trash-talkers in the UFC.

But in an interview with Inside MMA, “Rampage” revealed that he does not think Sonnen is able to back up his trash-talk with his actions.

“His mouth gets him his fights. What’s his name? How do you say his name? ‘Chael?’ His mouth gets his (expletive) in trouble,” Jackson said.

“He sounds like he practices his stuff in the mirror, and then he goes out and says it. He’s a great wrestler. That’s all I’m gonna say, ‘cause everything else sucks,” he added.

Jackson is also unimpressed with Sonnen’s effort against middleweight champion Anderson Silva at UFC 117, when he came close to dethroning the Brazilian legend.

“Look at what he did to Anderson Silva. He did a great job of holding him down, making a boring fighter out of a decorated champion, for five rounds. After the fight, I see that Anderson Silva didn’t have a mark on him. Not a mark,” Jackson pointed out.

Jackson admitted that he also talks trash as a fighter, but knows that he has limits.

“I talk trash about the people I’m actually gonna fight – people in my weight class,” he explained.